Rosacea is a chronic disease of inflammatory dermatitis that mainly affects the median part of the face and the eyelids of certain adults. It is characterized by telangiectatic erythema, dryness of the skin, papules and pustules. Conventionally, rosacea develops in adults from the ages of 30 to 50; it more frequently affects women, although the condition is generally more severe in men. Rosacea is a primitively vascular condition whose inflammatory stage lacks the cysts and comedones characteristic of common acne.
Factors that have been described as possibly contributing towards the development of rosacea include for example: the presence of parasites such as the Demodex folliculorum, the presence of bacteria such as Helicobacter pylori (a bacterium associated with gastrointestinal disorders), hormonal factors (such as endocrine factors), climatic and immunological factors, and so forth.
Rosacea develops in four stages over several years, in spasms aggravated by variations in temperature, alcohol, spices, exposure to sunlight and stress.
The various stages of the disease are the following:
Stage 1: stage of erythema episodes. The patients have erythrosis spasms due to the sudden dilation of the arterioles of the face, which then take on a congestive, red appearance. These spasms are caused by the emotions, meals and temperature changes.
Stage 2: stage of couperosis, i.e., of permanent erythema with telangiectasia. Certain patients also have oedema on the cheeks and the forehead.
Stage 3: inflammatory stage (papularpostular rosacea) with appearance of inflammatory papules and pustules, but without affecting the sebaceous follicles and thus with absence of cysts and comedones.
Stage 4: rhinophyma stage. This late phase essentially affects men. The patients have a bumpy, voluminous red nose with sebaceous hyperplasia and fibrous reordering of the connective tissue.
Typical treatment of rosacea include oral or topical administration of antibiotics such as tetracyclines, salicylic acid, anti-fungal agents, steroids, metronidazole (an antibacterial agent) or with isotretinoin in severe cases, or even with anti-infectious agents such as azelaic acid.
US 20110052515 described a pharmaceutical/dermatological topically applicable formulation for treating rosacea, comprising at least one avermectin compound and benzoyl peroxide (BPO, an anti-acne agent).
Breneman et al. (Int. J. Derma. 43, 381-387 (2004)) reported the results of a double blind randomized vehicle-controlled clinical trial of once-daily BPO and clindamycin topical gel in the treatment of moderate to severe rosacea.
Montes et al. (Cutis, 32, 185-190 (1983)) disclosed the use of BPO dissolved in acetone gel formulation for the treatment of rosacea.
Wester et al. (J. Am. Acad. Derma. 24, 720-726 (1991)) related to the controlled release of BPO from porous microsphere polymeric systems in the treatment of acne.
These previous rosacea treatments with BPO alone or in combination with other agents, have been shown to have severe drawbacks such as irritation and intolerance phenomena, especially when they are administered for a prolonged period. On the other hand, these treatments are only suppressive and not curative, acting especially on the pustulous spasms occurring during the inflammatory stage.
Considering the chronic nature of rosacea, there is a need for a prolonged use treatment of the disease, its symptoms and associated conditions, in a safe and effective manner. Thus, there exists a need for compositions that show improved efficacy in the treatment of rosacea, that impart greater tolerance to the active principles and that do not have the side effects described in the prior art.